ABSTRACT
A 56-year-old woman with new-onset aphasia and mood changes was diagnosed with a left temporal mass. The surgery was done. She was referred for a trial of post-operative study of in vivo evaluation of CXCR4 expression using [68Ga]Ga-Pentixafor (Pars-CixaforTM) PET/CT in high-grade glioma. The imaging from the brain revealed no evidence of tumoral remnant. Furthermore, the patient represented positive COVID-19 PCR about 4 weeks prior to the study. Surprisingly, mild diffuse uptake was noted in the base and periphery of both lungs with ground glass opacities (GGO) and consolidations (SUVmax = 2.60) with CXCR4-avid hilar lymph nodes (SUVmax up to 3.42).Copyright © 2023 The Authors.
ABSTRACT
Background: Lymphoma is one of the most common primary malignancies of the hematopoietic system. Lymphoid neoplasms are classified into Hodgkin’s and Non-Hodgkin’s lymphoma. Non-Hodgkin lymphoma accounts for about 5% of all cases of malignancies, It is less predictable than Hodgkin lymphoma and more liable for extra-nodal spread. Males are slightly more affected than females with higher incidence in white population. B-cell lymphomas have higher incidence in adults while T-cell lymphomas have higher incidence in children. With many imaging modalities that can describe the morphological changes in lymph nodes, it’s almost exclusive for the PET/CT to describe the biological changes in those lymph nodes through their uptake of FDG which has a great value in determining whether those lymph nodes are affected or not, which in turn will play an important role in treatment & management plan. What gives PET/CT scan the upper hand is that it acts on the biological level of the cells which permit early discovering of the affected lymph nodes, much earlier than standard C.T or MRI scan.
ABSTRACT
Background-Aim: The aim of the present study was to investigate the occurrence and characteristics of axillary lymph node hypermetabolism (ALNH) after COVID-19 vaccination in a large series of cancer patients undergoing 18F-FDG PET/CT. Methods: We retrospectively reviewed a consecutive series of 500 cancer patients (267 males and 233 females, aged 22-91 years, mean age: 64.9 years) who underwent 18F-FDG PET/CT after COVID-19 vaccination (period: March-October 2021). Twenty of these patients were studied twice for a total of 520 PET/CT studies;135/520 studies were carried out after the first dose of vaccine and the remaining 385/520 studies after the second dose. All FDG PET/CT studies were acquired at the same nuclear medicine Centre according to standardized acquisition procedure protocols, using a Discovery 710 system (GE Healthcare). PET images were analysed both qualitatively and semiquantitatively calculating SUV max at the level of hypermetabolic lymph nodes. Results: ALNH ipsilateral to COVID-19 vaccination was observed in 176/520 studies (33.8%). Among the 176 positive studies, HALN was considered vaccine-related (Group 1) in 130/176 cases (74%), metastatic (Group 2) in 34/176 cases (19.3%) and equivocal (Group 3) in the remaining 12/176 cases (6.8%). SUV max was 3.5 ± 2.21 in Group 1, 8.95 ± 5.83 in Group 2 and 3.912 ± 1.66 in Group 3 (p<0.0001). Among the 130 Group 1 cases, 31 were studied after vaccine dose 1 (subgroup 1A) and 99 after vaccine dose 2 (subgroup 1B) with SUV max equal to 3.12 ± 1.72 in the former subgroup and 3.62 ± 2.34 in the second subgroup (p = 0.27). Furthermore, in the subgroup 1A, SUV max was 3.68 ± 2.01 in the first week after vaccination, 2.76 ± 1.57 in the second week and 2.52 ± 1.2 in the third week (p = 0.567), while in the subgroup 1B the corresponding SUV max values were 5.51 ± 3.03, 3.81 ± 2.01 and 3.17 ± 1.96 (p<0.001). After third week post-vaccination, FDG lymph node avidity was observed in 2/31 subgroup 1A cases and in 27/99 subgroup 1B cases. Conclusions: In our series, the overall prevalence of vaccine-related ALNH was 25% (130/520). Vaccine-related hypermetabolic lymph nodes showed a significantly lower SUV max than that observed in metastatic lymph nodes. Equivocal findings were seen in<7% of cases. No statistically significant difference in SUV max was seen after dose 1 and dose 2 vaccinations. However, after the second vaccination, the SUV max was statistically higher in the first week rather than later. Finally, FDG lymph node uptake may persist beyond the third week, mainly after the second vaccination.
ABSTRACT
Background: Fever of unknown origin (FUO) is a challenging clinical problem in medicine that needs collaboration of various diagnostic techniques to establish the accurate diagnosis. We evaluated the diagnostic performance of 18F-FDG PET/CT in patients who presented themselves with FUO. Our study included 40 patients with FUO who underwent PET/CT examination and their results were compared to the results of laboratory, histopathological, microbiological investigations and/or response to therapy. Results: The final diagnosis included malignancy in 20 patients (50%), infectious causes in 7 patients (17.5%) and non-infectious inflammatory causes in 6 patients (15%). Fever resolved without diagnosis in 4 patients (10%), while no definite diagnosis was reached in 3 patients (7%). PET/CT successfully contributed to diagnosis of 35 out of 40 patients with diagnostic accuracy of 87.5%. The sensitivity, specificity, positive predictive value and negative predictive value of PET/CT in our study were 93.5%, 66.7%, 90.6% and 75%, respectively. Conclusion: PET/CT is a useful tool to investigate and diagnose the cause of FUO. It provides information that can guide the treatment strategy of the patients.